Ragged edges on a PLA print

Overnight last night I printed 30 cable chain links from Thingiverse, and they all came out looking like this, as if something had nibbled at the edges. Not seeing any rabbits or parrots or hamsters around, I assume there’s something going on in my slicer settings. This is rainbow silk PLA using basically the stock generic PLA profile in Cura. Any idea what is going on here? I’m currently running another test print with a retraction speed of 25 instead of 50 to see if that will help.


Looks like insufficient cooling. The overhangs seem to be sagging down. Depending how the tool heat cooling is done, you can try to turn the object 90°, so the air comes from the other direction.

Retract could be another reason, but since the problem is only below the object and not on the upper roundings, I think it is the lack of cooling.

Good observation @Geit. There really is a huge difference between the upper & lower rounds.


I think you may be onto something. Here’s the parts cooling fan duct. Garbage!

Now printing one of the several alternatives on Thingiverse. Wish me luck!

I don’t remember ever having that problem. I’ve probably had all the others.

Mind you, the OP did say he’s using silk PLA. I suspect that has something to do with the problem, as I understand silk PLA has some unique issues & concerns.

In my experience most filaments from the same vendor print the same and the color does not matter. At least when it comes to temperature changing, translucent and glowing features I did not experience any difference.

It of course could be that there are additives that are not as heat “consuming”, so the entire energy from heating goes through the material and causes the sagging. Like fiber or wood.

If he would print the same chain using a normal pla, he can be certain, what is causing it.

Good point. I would definitely try printing with normal PLA.

I print a lot with various silk metallic PLA. They printed well until my heat creep problem crept back. In fact they can be dazzling.

The problem was due to the parts cooling fan duct being almost entirely constricted. I posted a picture yesterday but it got spam-trapped and is still awaiting moderation. I printed a new one and now those parts are coming out perfectly.

So @Geit is correct: not enough cooling.